(a) Field of the Invention
This invention relates to (pyridinyl)-Y-benzimidazol-2-ols, -2-thiols and lower-alkyl ethers derivatives thereof, their preparation and their use as cardiotonic agents, where Y is a direct linkage or lower-alkylene.
(b) Description of the Prior Art
Zubarovakii et al. [(Inst. Org. Khim., Kiev, USSR) Khim. Geterotsikl. Soedin. 1972, (5), 687-90 (Russ.); C.A. 77, 141,468k (1972)], in a paper entitled "Synthesis of Benzimidazole Derivatives. V. Pyridylbenzimidazoles and Cyanine Dyes From Them" disclose, inter alia, the monohydrochloride of 2-methyl-5-(2-pyridinyl)-1H-benzimidazole, 1-ethyl-2-methyl-5-(2-pyridinyl)-1H-benzimidazole and 2-methyl-1-(2-pyridinyl)-1H-benzimidazole, all as intermediates for preparing cyanine dyes.
The abstract of Lauer and Walser U.S. Pat. No. 4,026,936, issued May 31, 1977, discloses "compounds represented by the formula ##STR1## wherein R is ##STR2## or --(CH.sub.2).sub.n --R', R' is 2-pyridyl, 3-pyridyl, 4-pyridyl or 2-thiazyl, R.sup.2 is lower alkyl and n is 1 or 2, and acid addition salts of the compounds wherein R' is 2-pyridyl, 3-pyridyl or 4-pyridyl are disclosed as useful as anthelmintics against a broad spectrum of helminths." Specifically disclosed as Example 36 (column 16, lines 47-67) is methyl [5(6)-2-pyridinylmethyl)-2-benzimidazolyl]carbamate.